Method of producing a high octane gasoline by reforming a naphtha in two stages



B. S. FRIEDMA METHOD OF PRODUCIN" Aug. 2, 1960 (1 A HIGH OCTANE GASOLINENAPHTHA IN TWO STAGES BY REFORMING A Filed Dec. 3, 1956 INVENTOR BERNARDS.

FRIEDMAN bed.

employed metal present in these reforming catalysts although otheruseful platinum metals include rhodium, palladium, iridium which, alongwith platinum, are the face centered cubic crystallite types of theplatinum family as' distinct from the hexagonal types ruthenium andosmium which appear to be of lesser value.

These catalysts can be made by a number of procedures but a particularlyeffective catalyst is one in which the alumina is obtained throughcalcination of an alumina hydrate containing at' least about 65 weightpercent of trihydrate and about 5 to 35 weight percent of aluminamonohydrate and/ or amorphous alumina forms, and advantageously having asurface area of about 350 to about 550 square meters per gram (BETmethod) when in the virgin state. The minor amount of platinum metal inthe catalyst is usually present in finely divided form and is notdetectable by X-ray diffraction techniques. Also, these'catalysts areadvantageously prepared to afford about 0.10 to 0.5, preferably about0.15 to 0.3 cc./ gram catalyst.

The platinum metal-alumina catalyst can be employed in any type ofreaction system desired, for instance moving or fluidized bed,regenerative or non-regenerative, etc.,

but advantageously the catalyst is disposed as a fixed V In the lattertype of operation the size of commercial units is such that essentiallyadiabatic reaction systems must be employed and in view of this and theendothermic nature of the reforming operation the catalyst is placed infixed beds in a plurality of reactors, each of which is preceded bymeans for heating its charge. In fixed bed operations the catalyst is inmacrosize form, that is particles generally at least about 4 in lengthand diameter and preferably not exceeding about in diameter.Particularly when such particles are provided by extrusion, their lengthmay be up to about 1" or more. If the platinum metal-alumina catalystreforming system be of the regenerative type it can be arranged so thatthe catalyst of all of the reactors can be regenerated simultaneously orindividually. Other variations in the platinum metal catalyst reactionsystem can be made according to the desires of the operator.

The essential feed to my hydrogen fluoride-boron trifluoride catalystsystem contains a substantial part or all of the liquid reformate fromthe platinum metal catalyst operation and as noted above the over-allhydrohydrogen fluoride-boron trifiuoride reaction system can be returnedto the system or various materials such as straight run naphthas,thermal or catalytically cracked gasolines and their fractions can beadded. I prefer that the charge to the hydrogen fluoride-borontrifiuoride reaction zone be composed of at least about 50 weightpercent of reformate from the platinum metal-alumina catalyst reactionsystem or a fraction thereof boiling over a range. of at least about 100F., preferably over a range of at least about 200 F. The hydrogenfluoride- ,boron trifiuoride catalyst can be employed in the substantialabsence of added free hydrogen. However, such a gas can be employed tominimize sludge and heavy oil formation. When using hydrogen I preferabout 1 to 10 moles per mole of hydrocarbon feed. Paratfins such borontrifiuoride reaction zone can be separated in a Should agitation of thereaction mixformer.

tained must be suflicient to provide essentially liquid phase reactionconditions as determined by the vapor pressure of the hydrogen fluoride,boron trifiuoride, the reactants and other materials such as hydrogenand reaction products present. Generally, the pressure will be aboveatmospheric in maintaining the liquid phase reaction. The reactiontemperature and time are interdependent factors With a lesser timerequired to provide products of given octane as the temperatureincreases. The reaction temperature will usually be in the range ofabout 50 to 300 F., preferably at least about F.,

with the time required ranging from about /2 minute to 5 hours,preferably about. 10 minutes to 1 hours. Times longer than 5 hours canbe employed; however, no particular advantage has been derived therebywhich overcomes the obvious economic disadvantages. Inthe reaction zoneat least about 0.75, preferably at least about 1.0, mole of borontrifiuoride is provided in the liquid phase per mole of aromaticspresent and due to economic considerations this ratio will usually notexceed about 5 to 1 or even about 2 to 1. In general I employ at leastabout 0.5, preferably about 1 to 10, moles of hydrogen fluoride per moleof aromatic constituent. These catalytic components can be addedseparately but preferably they are introduced into the reaction zone inadmixture. The hydrogen fluoride-boron trifiuoride reaction system isusually conducted essentially in the absence of water to avoid having toincrease the amount of boron trifiuoride, but frequently there are minoramounts of water present such as those derived through the use ofcommercially available hydrogen fluoride and boron trifiuoride. Thepressure in this reaction system is sufficient to maintain the liquidphase reaction and frequently is in the range of about 400 to 1500p.s.i.g.

The hydrocarbon product from the hydrogen fluoridenumber of ways. turebe stopped it will generally separate into two phases in the reactor orin any other vessel into which it is transferred as in a continuous,semi-continuous or batch operation. Regardless of where the phaseseparation takes place or if the formation of these phases is preventedby continuous agitation, the catalyst and hydrocarbon ma terials can beseparated by any desired procedure. For instance, the over-all productcontaining both the catalyst and hydrocarbon can be water washed toremovethe Preferably, however, in this type of system I reduce thepressure maintained on the reaction product to allow the borontrifiuoride and then the hydrogen fluoride to distill or be flashed andthis operation is followed by water washing to remove remainingcatalyst. Alternatively, only the boron trifiuoride might be distilledwhich would permit the hydrogen fluoride to separate from thehydrocarbon by gravity and the'hydrocarbon layer could then be decantedand water washed.

In another type of system the reaction mixture could be allowed toseparate into a lower layer of catalyst containing aromatics which canbe recycled to the reaction system in whole or in part; The upperhydrocarbon layer formed could be freed from catalyst by distillationand/or washing with Water or passed through a column layer could beseparated as by distillation of the catalyst,

"storms-s v s fan'd the aromatics mightthen be combinedfwiththeihydrocarbons of the upperlayer'to providea higher octane product.Small traces of fluoride remainingimthehydrocarbon material can beremoved as by pass'age over aluminum or-alumina-at 200-10 400 -F.Various drying procedures could be employedtoseparate water from thehydrocarbon materialsandsuchmaterials could; be stabilized, forinstanee-by-theremova1of Cis-arid lighter bonstituefits.

ln the'drawing I have illustrated a simplified flow sheet of anoperation conducted -in accordance with my method.

;I n this-=systemstraight run naphtha ischarged by way 0f linedto-heaterl and then-through line-3 to aninitial reactor 4 which-contains.a fixed-.bed of platinum-alumina catalyst. The eflluent from reactor 4is passed-by way of =-line -5to-heater 6-and then through-line 7 to asecond reactor 8 containing platinum alumina catalyst. Therplatinum-alumina catalyst reaction section is of the adiabatic type andrnore than two reactors can be pro- "vided if desired and-in factusually at least three catalyst .b'eds -in separate reactors will be"employed with each --reactor=having associated therewith afeedrpreheater.

The reformate from reactor S-is passed by way of line 9 toatmospherioflash drum 10 which separates C s and .Qlighter materialswhich arepassed through -line ll to separator 12. The separator.provides for removal of C a to hydrocarbon constituents through line 13and hydrogemand methane are passed byway of line 14 to'line 1.-Excess-hydrogen :and methane can be removed from -line:1'4 by wayofline 15.

The aliqu-idwhydrocarbon I reformate from flash drum -l0' is-conveyed byway of line :16'toreactor 17 where it is -eontacted with the hydrogenfluoride-boron trifiuoride Tcatalystenteringbyway-of line 18. Thereaction mixture is-continuously withdrawnfrom reactor 17 and passed byway of line :19 to separation section 20. The hydrogenfluoride-borontrifiuoride catalyst separated from the hydrocarbonproduct can-berecycledby -way of-line 18 to reactor -17. The -liquidhydrocarbon @product obtained -from separation section ztl isconveyed tofractionator 21 by way ofline-22 which" separates -C s and lightermauterialsoverhead'by way of line2 3, motor -fuel boiling:rangelproducts by way of line it 24, and heavier -hydrocarbon s asbottoms through linezfi. i The-following specificexamples will servetoillustrate uthe-gpresent inventionthowever, they are not to be -con-:sidered limiting.

Example-I iAstraighfrun naphtha is obtained by distillation fromcrud'efoil and the naphthatypically has an ASTM distillation boilingrangeo'f about 195 to '3 80 F and a RON 7":(ne2t) "of about 44.8. Thisnaphtha is 'fedito a reforming containing "threeessentially adiabaticreactors each :having a' fixed bed-of a platinum-alumina reformingcatalyst. -This systemis equipped with means forheating the chargetoeach-reactorand the heaters-landreactors are arranged for serial how.The catalyst employed is a .-rplatinum aluminareforming catalystcontaining about 0.6 weight percent platinum and manufactured inaccordance with application Serial No. 489,726, listed above. The inlettemperatures of thefeed to thethree-catalyst beds are 946, 936 -and926"=F., respectively, while the pressure ..is about 500 p.s.i.g. Freehydrogen is supplied to the free-amassing to'the 'heaterbe'forethe-first reactor and ."lflie h y'drlogen'is obtained by recycle fromthe third-reactor Eifiuent stream. 'The molar ratioof hydrogenrich-recycle as to'liydrocarboh feed is approximately 7.3 to 1. 0 whilethe ever-an spacevlocity is"about"2.26 WHSV. The efiiuent from the lastreactor is conveyed to a flash drum operating at 500 p.s.i.g. and isthen treated or depropanized to remove C and lighter hydrocarbons bydistillation. Inspection on the resulting reformate is as follows:

418. grams of'the reformate is'distilled'to obtain 91I5 weight percentof C gasoline and 4.67 weight percent of butanes (iso-I-normal).lns'pec'tio'non .thefstabilized gasoline fraction is as follows:

ASTM distillation, *F.:

300 grams of the 95 '3 90 F. reformate isplacedina cool 1750 ml.stainless steel Magnedas'h bonibhaVing tapered Walls to give maximumthickness in thebottom half of the bomb. To the cool bomb is added 10n1oles of hydrogen fluoride. The bomb is sealed and charged with 6.4moles ofbo'ron trifluoride by pressuring from a 2- liter cylinder fittedwith apressure. gauge. Theamounta'of borontrilluc'iride introduced isestimated by interpolation from the data of Kilpatrick and Luborsky,I.A.C.S. 76, 5 866 (1954). While stirring the contents of thewbombwit isheated for 65 minutes to reach F. This temperature is held for 30minutes and the pressure reaches a maximum of 880 p.s.i.g. Thecontentsof the bomb .are

his-char ed through the bottomdraw-ofi int'o amixt'u're ofice'and water.IG'ases are conducted through aDry- Ice co'olin'gitra'p, safety trap,water scrubben g'as "sampler "and Wet test meter. The hydrocarbonlayeriis separated fr'omth'e 'i'cewater and'the former is 'Washedfthreetimes with separate 500 cc. portions of water. The Washed hydrocarbon isdried by contact with potassium carbonate. Theproducts obtained are271.5 .grams of liquid hydrocarbon, 10:5 grains of condnsable 'gasand--3.-2 '1itrs (STP) of drygas. The*condensable gas-and liq'uid arethen combined and distilled through-a 12 =glas's helices,vacuum-jacketed distillation -column to separate 4118 weightpercent of C43 wet gas, 79.3Weight percent of initial*to400 F. overhead gasoline and7.-17-Weight:p.er-

'cent of a s'tillresidue boiling above 400 F. The'yield of gasoline whencorrected forhandlingiand'mechanical losses is about 87.8 weight percentand since=the-gaseline fraction has a 378 F. end point the yield w'o'uldbe increased by distilling to 435 F. to obtain the usual nominal 410 endpoint gasoline. Inspection of the :gasoline fraction is as follows:

ASTM distillation, F

RON 9356 (neat).

. 1 0l (3'. ;'c. 1 l V 'addedfgalfi). Aro n'fafics s '4 9.5%- Olefins0.4%.

Thus by treating the reformate from the platinum-alumina catalyst systemwith the hydrogen fluoride-boron trifluoride catalyst the clear researchoctane number of the 426 grams of the reformate produced in theplatinumalumina catalyst system of Example I is placed in the magnedashbomb described in Example I. To the cool bomb is added 5.37 moles ofhydrogen fluoride. The bomb is sealed and charged with 3.15 moles ofboron trifluoride by pressuring as in Example I. While stirring thecontents of the bomb it is heated for 97 minutes to reach 245 F. Thistemperature is held for 30 minutes and the pressure reaches a maximum of975 p.s.i.g. The bomb contents are discharged and worked up as inExample I. liquid hydrocarbon, 8.0 grams of condensable gas and 3.07liters (STP) of dry gas. The condensable gas and liquid are thencombined and distilled through a 12" glass helices, vacuum-jacketeddistillation column to separate 10.55 Weight percent of C 43 wet gas,73.1 Weight percent of initial to 400 F. overhead gasoline and 8.46weight percent of a still residue boiling above 400 F. The yield ofgasoline when corrected for handling and mechanical losses is about 79.4weight percent and since the gasoline fraction has a 370 F. end pointthe yield would be increased by distilling to 435 F. to obtain the usualnominal 410 F. end point gasoline. Inspection of the gasoline fractionis as follows:

ASTM distillation, F.:

I.B.P 113.

RON 95.0 (neat),

. 100.5 (3 ct. TEL

added/ gal.

Aromatics 49.6% Olefins 0.5%. R.V.P 4.95 lbs.

Thus by treating the reformate from the platinum-alumina catalyst systemwith the hydrogen fluoride-boron trifluoride catalyst the clear researchoctane number of the resulting stabilized gasoline was increased by 6.3num bers and the higher octane product showed a good leadsusceptibility.

Example III 5.4 moles of hydrogen fluoride is added to the Magnedashbomb described in Example I. The bomb is sealed and charged with 3.2moles of boron trifluoride by pressuring from a cylinder as inExample 1. While stirring, the bomb is heated to a temperature of 250 F.and 380 grams of the reformate obtained in the platinum-alumina catalystoperation of Example I is charged by forcing the hydrocarbon feed from acharger under nitrogen pressure. The 250 F. temperature is then held for22 minutes and the pressure reaches a maximum of 1110 p.s.i.g. The bombcontents are discharged through the bottom draw-01f into' a mixture ofice and water and Worked up as in Example I. The products are 352.0grams of liquid hydrocarbon, 13.0'grams of condensable gas and 3.95liters (STP) of dry gas. The condensable gas and liquid are thencombined and distilled through a 12" glass helices, vacuum-jacketeddistillation column to separate 9.88 weight per cent of C -C W6t gas,73.18 weight percent of initial to 400 F. overhead gasoline and 9.74weight percent of still residue boiling over 400 F. Correcting formechanical and distillation losses the yield of initial to 400 F.gasoline is about 79 Weight percent and this could be increased bytaking the distilla- The products obtained are 401.0 grams of g tionoverhead to 435 F. to secure the usual nominal 410 F. end pointgasoline. Inspection of the gasoline fraction is as follows:

ASTM distillation, F.: r r I I.B.P 111.

E.P 370. f RON 95.5 (neat). R.V.P 5.65 lbs; 'Aromatics 55.2%. Olefins0.4%.

These data show the substantial increase in octane of the stabilizedgasoline afforded by the operation using the hydrogen fluoride-borontrifluoride catalyst.

I claim:

1. In a method for the conversion of a straight run hydrocarbon fractionboiling in the motor fuel range, the steps comprising contacting saidhydrocarbon fraction with a platinum metal-alumina catalyst in thepresence of free hydrogen at a temperature of about 750 to 1000 F. and apressure of about 50 to 1000 p.s.i.g to provide a product boiling in themotor fuel range of increased octane value, separating a resultinghydrocarbon liquid productboiling over a range of at least about F.,contacting with a catalyst consisting essentially of hydrogen fluorideand boron trifluoride, a hydrocarbon material containing a substantialamount of said separated product, said hydrocarbon material boiling inthe motor fuel range and containing about 20 to 80 weight percent ofaromatics at a temperature of about 50 to 300 F. and a pressuresuflicient to maintain the liquid phase to provide a further increase inthe octane quality of the product boiling in the motor fuel range, thecontacted hydrogen fluoride, boron trifluoride and hydrocarbon includingat least about 0.75 mole of boron trifluoride and about 0.5 to 10 molesof hydrogen fluoride per mole of aromatic in the hydrocarbon andseparating a motor fuel boiling range hydrocarbon of high octanequality.

2. In a method for the conversion of a straight run hydrocarbon fractionboiling in the motor fuel range, the steps comprising contacting saidhydrocarbon fraction with a platinum-alumina catalyst in the presence offree hydrogen at a temperature of about 825 to 975 F. and a pressure ofabout to 500 p.s.i.g. to provide a product boiling in the motor fuelrange of increased octane value, separating a resulting hydrocarbonliquid product boiling over a range of at least about 200 F. andcontaining about 30 to 60 weight percent of aromatics, contacting saidseparated liquid productwith a catalyst consisting essentially ofhydrogen fluoride and boron trifluoride at a temperature of about 150to300 F. and a pressure of about .400 to 1500 p.s.i.g. and suflicient tomaintain the liquid phase to provide afurther increase in the octanequality of the product boiling in the motor fuel range, the contactedhydrogen fluoride, boron trifluoride and hydrocarbon including about 1to 2 moles of boron trifluoride and about 1 to 10 moles of hydrogenfluoride per mole of aromatic in the hydrocarbon and separating a motorfuel boiling range hydrocarbon of high octane quality; i

References Cited in the file of this patent "UNITED STATES PATENTS BurkAug. 17, 1948 2,513,103 Passino June 27, 1950 2,758,062 Arundale Aug. 7,1956 2,781,298 Haensel et a1 Feb. 12, 1957 2,849,376 Watson Aug. 26,1958

2. IN A METHOD FOR THE CONVERSION OF A STRAINGHT RUN HYDROCARBONFRACTION BOILING IN THE MOTOR FUEL RANGE THE STEPS COMPRISING CONTACTINGSAID HYDROCARBON FRACTION WITH A PLATINUM-ALUMINUM CATALYST IN THEPRESENCE OF FREE HYDROGEN AT A TEMPERATURE OF ABOUT 825 TO 975* F. AND APRESSURE OF ABOUT 150 TO 500 P.S.I.G. TO PROVIDE A PRODUCT BOILING INTHE MOTOR FUEL RANGE OF INCREASED OCTANE VALUE, SEPARATING A RESULTINGHYDROCARBON LIQUID PRODUCT BOILING OVER A RANGE OF AT LEAST ABOUT 200*F. AND CONTAINING ABOUT 30 TO 60 WEIGHT PERCENT OF AROMATICS, CONTACTINGSAID SEPARATED LIQUID PRODUCT WITH A CATALYST CONSISTING ESSENTIALLY OFHYDROGEN FLUORIDE AND BORON TRIFLUORIDE AT A TEMPERATURE OF ABOUT 150 TO300* F. AND A PRESSURE OF ABOUT 400 TO 1500 P.S.I.G. AND SUFFICIENT TOMAINTAIN THE LIQUID PHASE TO PROVIDE A FURTHER INCREASE IN THE OCTANEQUALITY OF THE PRODUCT BOILING IN THE MOTOR FUEL RANGE, THE CONTACTEDHYDROGEN FLUORIDE, BORON TRIFLUORIDE AND HYDRCARBON INCLUDING ABOUT 1 TO2 MOLES OF BORON TRIFFLUORIDE AND ABOUT 1 TO 10 MOLES OF HYDROGENFLUORIDE PER MOLE OF AROMATIC IN THE HYDROCARBON AND SEPARATING A MOTORFUEL BOILING RANGE HYDROCARBON OF HIGH OCTANE QUALITY.